Evidence not found to support use of 'ankle brachial index' to gauge heart risks
TUESDAY, Sept. 3, 2013 (HealthDay News) -- A simple test of blood pressure in the ankle may help gauge heart disease risk for adults without any symptoms, but a U.S. government-appointed panel says there's not enough evidence to recommend it for routine checks.
In its final recommendation, released Tuesday, the U.S. Preventive Services Task Force said it's unclear whether using the "ankle brachial index" to screen for peripheral artery disease (PAD) and assess the risk of heart disease is beneficial in people with no symptoms.
"We recognize this is a common problem and PAD afflicts many Americans," said task force co-vice chair Dr. Albert Siu. "And we recognize it's a common cardiovascular risk factor, but we don't know, in the absence of symptoms, whether this test is useful or not."
The statement by the task force, an independent panel that advises the federal government on the effectiveness of various medical interventions, doesn't apply to people with symptoms of peripheral artery disease. People with symptoms should see a doctor and be diagnosed, Siu said.
Peripheral artery disease is a narrowing of the arteries in the pelvis and legs, and like heart disease, restricts the blood supply to the heart. The condition, which becomes more common with age, often goes undiagnosed and people who have it face four to five times more risk of heart attack or stroke, according to the American Heart Association (AHA) website.
The most common symptoms are cramping, pain or tiredness in the leg or hip muscles while walking or climbing stairs. Typically, this pain goes away with rest and returns when walking again.
Peripheral artery disease is most often diagnosed with the ankle brachial index, which compares the blood pressure in the feet with the blood pressure in the arms. In healthy people, the ankle pressure is at least 90 percent of arm pressure, but in PAD it may be less than 50 percent, according to the heart association.
The task force's recommendation appears in the Sept. 3 online issue of the Annals of Internal Medicine.
One expert agrees with the new recommendation.
"There are many logical reasons to think that screening for peripheral artery disease with the ankle brachial index and treating people who are screen-positive will prevent cardiovascular events," said Dr. Mary McGrae McDermott, author of an accompanying journal editorial.
Despite this, there are no rigorous trials that show screening for peripheral artery disease with the ankle brachial index improves outcomes, said McDermott, a professor of medicine at Northwestern University's Feinberg School of Medicine, in Chicago.
"Currently there is not high-quality evidence to demonstrate that screening for peripheral artery disease with the ankle brachial index reduces cardiovascular event rates," she said.
Another expert, however, said the task force's recommendation is at odds with current guidelines from other professional organizations.
"This new systemic evidence review by the U.S. Preventive Services Task Force, which tends to be very conservative in its review and interpretation of evidence, concludes that the ankle brachial index may be of limited value and there is need for further studies," said Dr. Gregg Fonarow, an AHA spokesman and professor of cardiology at the University of California, Los Angeles.
However, Fonarow said, a guideline from the American College of Cardiology Foundation and the American Heart Association recommends that "measurement of ankle brachial index is reasonable for cardiovascular risk assessment in asymptomatic [symptomless] adults at intermediate risk."
Peripheral artery disease is usually treated with blood pressure medications and cholesterol-lowering drugs. Some patients, however, may need minimally invasive treatment or surgery to open their narrow arteries. Left untreated, peripheral artery can lead to gangrene and amputation. The condition affects about 8 million Americans, according to the heart association.
For more on peripheral arterial disease, visit the American Heart Association (http://www.heart.org/HEARTORG/Conditions/More/PeripheralArteryDisease/Peripheral-Artery-Disease-PAD_UCM_002082_SubHomePage.jsp ).
SOURCES: Albert Siu, M.D., M.S.P.H., co-vice chair, U.S. Preventive Services Task Force; Mary McGrae McDermott, M.D., professor of medicine and preventive medicine, Northwestern University Feinberg School of Medicine, Chicago; Gregg Fonarow, M.D., spokesman, American Heart Association, and professor, cardiology, University of California, Los Angeles; Sept. 3, 2013, Annals of Internal Medicine